| Small block Chevy engine project |
Last updated on January 19, 2008 |
Zora Arkus-Duntov's Memo to Chevrolet
Thoughts Pertaining to Youth, Hot Rodders, and Chevrolet
The Hot Rod movement and interest in things connected with hop-up and speed is still growing. As an indication:
the publications devoted to hot rodding and hop-upping, of which some half-dozen have a very large circulation and
are distributed nationally, did not exist some six years ago.
From cover to cover, they are full of Fords. This is not surprising that the majority of hot rodders are eating,
sleeping, and dreaming modified Fords. They know Ford parts from stern to stern better than Ford people
themselves.
A young man buying a magazine for the first time immediately becomes introduced to Ford. It is reasonable to
assume that when hot rodders or hot rod-influenced persons buy transportation, they buy Fords. As they progress in
age and income, they graduate from jalopies to second-hand Fords, then to new Fords.
Should we consider that it would be desirable to make these youths Chevrolet-minded? I think that we are in a
position to carry out a successful attempt. However, there are many factors against us:
Loyalty and experience with Ford.
Hop-up industry is geared with Ford.
Law of numbers: thousands are and will be working on Fords for active competition.
Appearance of Ford’s overhead V-8, now one year ahead of us.
When a superior line of GM V-8s appeared, there where remarkably few attempts to develop these, and none too
successful. Also, the appearance of the V-8 Chrysler was met with reluctance even though the success of
Ardun-Fords conditioned them to the acceptance of Firepower.
This year is the first one in which isolated Chrysler development met with successes. The Bonneville records are
divided between Ardun-Fords and Chryslers.
Like all people, hot rodders are attracted by novelty. However, bitter experience has taught them that new
development is costly and long, and therefore they are extremely conservative. From my observation, it takes an
advanced hot rodder some three years to stumble toward the successful development of a new design. Overhead Fords
will be in this stable between 1956 and 1957.
The slide rule potential of our RPO V-8 engine is extremely high, but to let things run their natural course will
put us one year behind - and then not too many hot rodders will pick Chevrolet for development. One factor which
can largely overcome this handicap would be the availability of ready-engineered parts for higher output:
If the use of the Chevrolet engine would be made easy and the very first attempts would be crowned with success,
the appeal of the new RPO V-8 engine will take hold and not have the stigma of expensiveness like the Cadillac or
Chrysler, and a swing to Chevrolet may be anticipated. This means the development of a range of special parts -
camshafts, valves, springs, manifolds, pistons, and such - should be made available to the public.
To make good in this field, the RPO parts must pertain not only to the engine but to the chassis components as
well. In fact, the use of light alloys and brake development, such as composite drums and discs, are already on
the agenda of the Research and Development group.
These thoughts are offered for what they are worth: one man’s thinking aloud on the subject.
Signed,
Zora Arkus-Duntov
December 16, 1953
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The 2007 Chevy R07 NASCAR engine
April 14, 2007 GM press release
GM Racing White Paper: Inside the New Chevrolet R07 Small-Block V-8
Technical Insights on GM's First Purpose-Built Small-Block V-8 NASCAR Racing Engine
Detroit – For the first time since 1955, Team Chevy is introducing an all-new small-block V-8 engine in the top
tier of stock car racing. The new Chevrolet R07 is the first purpose-built engine designed and developed by GM
Racing specifically for NASCAR Nextel Cup competition. This purebred engine is the successor to the
production-based powerplants that have made Chevrolet the most successful manufacturer in NASCAR history. This
white paper highlights the Chevrolet R07's development and summarizes its technical features.
Design and Development
The Chevrolet R07 is succeeding the championship-winning SB2 (Small-Block/2nd Generation) engine that has been
used by GM teams in NASCAR Cup racing since 1998. NASCAR approved the Chevrolet R07 for competition in 2007, and
it is expected that the R07 small-block V-8 will become the exclusive Chevrolet powerplant in the Nextel Cup
series as teams turn over their inventory of SB2 engines and components.
Work on a successor to the SB2 began in earnest in 1999, and several variations of the conventional small-block
V-8 were designed, tested, and evaluated. In 2004, NASCAR held discussions with the automotive manufacturers about
a possible "Engine of the Future" that paralleled the Car of Tomorrow body/chassis program. Although the Engine of
the Future did not become reality, the meetings did establish a framework for future NASCAR engines.
"The discussions with NASCAR and the other manufacturers about the Engine of the Future were extremely
productive," said Jim Covey, NASCAR engine development manager for GM Racing. "Although the Engine of the Future
program was put on the shelf in 2005, NASCAR Nextel Cup Series director John Darby developed a list of parameters
that define the envelope for all manufacturers, thus giving Chevrolet an opportunity to develop the R07 engine.
This 'box' set the boundaries for specific design features and minimum and maximum dimensions for key engine
components.
"We had already started to lay the foundation for a future Chevrolet engine, and we were able to adapt that design
to the Chevrolet R07," Covey continued. "That was the key to designing, testing and submitting the engine for
approval on a very tight schedule. A prototype R07 engine was running durability tests on a dyno six months after
we kicked off the program. The R07 engine development team included Ed Keating and Ron Sperry, who focused on
cylinder heads and intake manifolds, and Ondrej Tomek, who was responsible for the cylinder block. We also worked
with our key Chevrolet teams, GM Powertrain, and our suppliers."
Just as in all forms of motorsports, the rulebook defined the basic engine package. GM Racing's objective was to
produce the most competitive and reliable engine within the boundaries established by NASCAR.
"NASCAR's box provides considerable latitude for manufacturers to design their engines, and there are many
parameters that have to be balanced," explained Pat Suhy, GM Racing Group Manager, Oval Track. "If a manufacturer
maximizes one aspect of the engine design then it may limit what can be done in another area. Our goal at GM
Racing was to find the optimum point for all of them. We relied on our computer-aided engineering and design
tools, our experience, and input from our affiliated teams to make informed decisions on the engine configuration.
It was all about balancing those tradeoffs to produce an engine that would produce competitive power with
exceptional reliability while also improving safety and reducing costs for Chevy teams."
Advanced Technology
Many of the advanced technical resources used by GM Racing engineers to develop the Chevrolet R07 racing engine
are also used to develop GM production engines. By employing technology such as computational fluid dynamics
(CFD), finite element analysis (FEA), and solid 3D modeling, GM Racing engineers were able to evaluate and analyze
various designs in computer simulations. This extensive use of computer modeling also accelerated the production
of prototype parts after the specifications were finalized.
While CFD is commonly associated with aerodynamic development of race cars, it can also be used to analyze the
behavior of fluids such as the coolant flow through the Chevrolet R07's block and cylinder heads. FEA was used to
analyze the strength and minimize the weight of the R07's block and cylinder heads.
"Although we use many of the same engineering tools, the timeframe for racing engines is much shorter than it is
for production engines," Suhy noted. "The rapid turnaround in racing allows us to get feedback on the accuracy of
GM's computer simulations and models very quickly. The same programs can then be refined to make them more
accurate when used to develop future production engines."
In this way, the Chevrolet R07 racing engine will lead to better production GM powerplants. "The concepts and
processes that are used to improve the performance of our racing engines are shared with the production engine
designers to improve the efficiency of our production engines," said Tom Stephens, group vice president of GM
Powertrain.
Technical Features
The Chevrolet R07 retains the pushrod/two-valve layout that has been the mainstay of American motorsports since
the introduction of the first-generation GM small-block V-8 in 1955. This classic design has now evolved into a
highly advanced racing engine.
Per NASCAR specifications, the Chevrolet R07 displaces a maximum of 358 cubic inches with a maximum cylinder bore
diameter of 4.185 inches. The block is a precision iron casting with integral oil and coolant passages that
eliminate the need for most exterior lines. The distance between the Chevrolet R07's cylinder bores is 4.500-inch
(vs. 4.400 inches in the SB2 small-block). This wider bore spacing improves coolant circulation around the
cylinder barrels. In conjunction with a targeted cooling system, the R07 block design minimizes temperatures at
critical locations.
The R07 block has a new six-bolt head bolt pattern instead of the small-block's traditional five-bolt design. The
revised head bolt pattern improves head gasket sealing and reduces cylinder bore distortion.
The R07's camshaft is located higher in the block than the camshaft in the SB2. The raised cam operates pushrods
that are correspondingly shorter and stiffer, thereby improving valvetrain dynamics at high rpm. The raised cam
also provides clearance for inboard piston squirters that spray the underside of the pistons with oil for cooling.
The camshaft tunnel is isolated from the crankcase to minimize windage losses caused by oil falling onto the
rotating crankshaft assembly from the cam and to contain the valvetrain parts in the event of breakage.
In contrast to the SB2's "mirror port" cylinder heads, the Chevrolet R07's aluminum cylinder heads resemble
production LS-series small-block cylinder heads with alternating intake and exhaust valves. The R07's shallow
valve angle produces a compact, efficient combustion chamber design that produces the required compression ratio
with a lightweight flat-top or slightly domed piston. GM Racing engineers optimized the R07's intake port layout
for the single, centrally mounted four-barrel carburetor mandated by NASCAR.
The aluminum intake manifold has an extended plenum to equalize fuel distribution among the cylinders. The
manifold is dry; a separate valley cover carries coolant from the cylinder heads. The R07's distributor is located
at the front of the engine to facilitate adjustments in ignition timing.
The Chevrolet R07 rocker covers are rigid cast aluminum with O-ring seals. The covers incorporate integral valve
spring oilers that are pressure fed from passages in the cylinder heads, eliminating the need for external oil
lines. GM Racing also designed a high-efficiency water pump and a carbon fiber front cover that shields the
aftermarket camshaft belt drives used by NASCAR teams.
The R07 has provisions for driving a conventional diaphragm fuel pump off of the camshaft. A remote-mounted
mechanical fuel pump can also be driven via a cable from the rear of the camshaft. When using the cable drive, the
fuel pump can be relocated to the rear of the car near the fuel cell. This enhances safety in an accident by
mounting the fuel pump in a less vulnerable location.
Key Partners
"Chevy NASCAR teams were deeply involved in the design of the Chevrolet R07," said Suhy. "We meet monthly with
representatives from our four key partners – Hendrick Motorsports, Richard Childress Racing, Joe Gibbs Racing
and Dale Earnhardt, Inc. – to get their input on how we can make Chevrolet racing engines more reliable and
easier to build and service. Many of their ideas were incorporated in the R07's final design, such as the
integration of the oil and cooling systems.
"It's not about helping our affiliated teams to build the most powerful engine because each of them has developed
their own proprietary parts and processes," he noted. "GM Racing's role is to provide premium quality, easy-to-use
components. We want Chevy teams to be able to devote more of their energy and resources to winning races and less
energy to preparing engines."
The introduction of the Chevrolet R07 small-block V-8 represents another milestone in the continuous evolution of
the small-block V-8 engine. GM's first purpose-built NASCAR racing engine was designed, built and tested to
continue Team Chevy's winning tradition in NASCAR.
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Our Chevy 327 engine project
On this page we'll follow the progress of building a mild and inexpensive 327 street engine for a
traditional '32 Ford coupe built with a late-Fifties or
early-Sixties theme. This engine won't be anything exotic, just some neat old parts and a bit of attention to
detail.
The project began in March of 2006, with a standard-bore, small-journal 327 block and a pair of 462 fuelie heads
that I found for sale here in Phoenix. The block was bought for $50, and the pair of heads cost another $100.
These parts are perfect for what this project is all about.
The dual-plane Brodix intake was found on eBay. It had been powdercoated silver, and used on a Camaro drag car.
Leaking race gas had stained the powdercoating, and it looked so bad nobody else wanted it. I won the auction for
$90, sandblasted it, and then worked it over with a variety of abrasives.
Back in 1993, when I lived just north of Charlotte, North Carolina, I bought this pair of 1960s Cal Custom
six-finned valve covers for $5. They are shown here after a bit of work with files and emery cloth. You can see
the result of filing and sanding the valve covers between the fins.
The Enderle timing cover was given to me by Russ Meeks, so what you see here cost me a total of $245.
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The casting number on the small-journal 327 block is 3858174.
Blocks with this casting number were used in cars that were made from 1964 through 1967, including the 1966
Corvette.
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Here is the right side of the block after it was sent out to SX Obsolete Engine Parts here in Phoenix, where it
was hot-tanked and acid-dipped.
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This the left side of the block after it was cleaned. We were hoping that all of the rust would be gone after the
acid-dipping, but the block had been outside for years and had a lot of rust on it.
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This the left side of the same block after I spent two hours working it over with abrasives.
After final machining and cleaning, the block will get painted to match the car. By prepping the outside of the
block this way, we'll have smooth, even surfaces under the paint, and it should look pretty good.
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Here's what the rear main cap looked like after the block was hot-tanked.
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This is the same main cap, after I spent a few minutes using small emery cloth cartridge rolls to put a radius
around the drain hole to make it easier for the oil to flow.
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Here's a close-up of the stock main cap.
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This is the same main cap after cleaning it up a bit and adding the radius.
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This picture was taken after the block was torn down, hot-tanked, inspected, and acid-dipped.
As they were found, the 462 heads were bare, clean, and in good shape.
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The intake ports are essentially untouched. They will be gasket-matched along with the Brodix intake.
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The combustion chambers have been smoothed out and the polishing has been started.
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The exhaust ports have been gasket-matched to a Fel-Pro copper gasket and shaped with abrasives. The next step is
to get them smoother.
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Here's one of the first valve covers Cal Custom made. Unlike the die-cast, six-finned valve covers that are shown
on the engine, this was sand-cast and has seven fins. This piece is NOS, and was likely made in the late '50s or
early '60s.
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This is a used pair of the early, seven-finned Cal Custom valve covers that were found on eBay. The castings are
rough, but they have been smoothed out with abrasives.
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When I bought a cherry Stewart Warner 9,000-rpm mechanical tach on eBay, the seller included an old dual-point,
tach-drive distributor.
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Here's a closer look at the dual-point distributor. Checking the number, 1110985, shows that it is the correct
piece for a 1962 Corvette.
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All text and images on Roadsters.com are Copyright 1996-2008 Dave Mann
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